In vivo bubble nucleation probability in sheep brain tissue

Gas nuclei exist naturally in living bodies. Their activation initiates cavitation activity, and is possible using short ultrasonic excitations of high amplitude. However, little is known about the nuclei population in vivo, and therefore about the rarefaction pressure required to form bubbles in tissue. A novel method dedicated to in vivo investigations was used here that combines passive and active cavitation detection with a multi-element linear ultrasound probe (4-7 MHz). Experiments were performed in vivo on the brain of trepanated sheep. Bubble nucleation was induced using a focused single-element transducer (central frequency 660 kHz, f-number = 1) driven by a high power (up to 5 kW) electric burst of two cycles. Successive passive recording and ultrafast active imaging were shown to allow detection of a single nucleation event in brain tissue in vivo. Experiments carried out on eight sheep allowed statistical studies of the bubble nucleation process. The nucleation probability was evaluated as a function of the peak negative pressure. No nucleation event could be detected with a peak negative pressure weaker than -12.7 MPa, i.e. one order of magnitude higher than the recommendations based on the mechanical index. Below this threshold, bubble nucleation in vivo in brain tissues is a random phenomenon.

Minimum Information about a Cardiac Electrophysiology Experiment (MICEE): standardised reporting for model reproducibility, interoperability, and data sharing

Cardiac experimental electrophysiology is in need of a well-defined Minimum Information Standard for recording, annotating, and reporting experimental data. As a step towards establishing this, we present a draft standard, called Minimum Information about a Cardiac Electrophysiology Experiment (MICEE). The ultimate goal is to develop a useful tool for cardiac electrophysiologists which facilitates and improves dissemination of the minimum information necessary for reproduction of cardiac electrophysiology research, allowing for easier comparison and utilisation of findings by others. It is hoped that this will enhance the integration of individual results into experimental, computational, and conceptual models. In its present form, this draft is intended for assessment and development by the research community. We invite the reader to join this effort, and, if deemed productive, implement the Minimum Information about a Cardiac Electrophysiology Experiment standard in their own work.

Catatonia from its creation to DSM-V: Considerations for ICD

Catatonia was delineated only as a type of schizophrenia in the many American Psychiatric Association DSM classifications and revisions from 1952 until 1994 when "catatonia secondary to a medical condition" was added. Since the 1970s the diagnosis of catatonia has been clarified as a syndrome of rigidity, posturing, mutism, negativism, and other motor signs of acute onset. It is found in about 10% of psychiatric hospital admissions, in patients with depressed and manic mood states and in toxic states. It is quickly treatable to remission by benzodiazepines and by ECT. The DSM-V revision proposes catatonia in two major diagnostic classes, specifiers for 10 principal diagnoses, and deletion of the designation of schizophrenia, catatonic type. This complex recommendation serves no clinical or research purpose and confuses treatment options. Catatonia is best considered in the proposed ICD revision as a unique syndrome of multiple forms warranting a single unique defined class similar to that of delirium.

Multimodal imaging of an astrocytoma affecting the amygdalar region

Introduction

Regional alterations of serotonergic neurotransmission and functional activation in the amygdalar region of patients with major depression are underpinning its important role in affective disorders. In this study we used fMRI and PET to describe functional and molecular alterations associtated with an astrocytoma in the left amygdalar region in a patient with organic depressive disorder compared to control subjects.

Methods

The serotonin-1A (5-HT1A) receptor binding (BPND) was quantified with PET (30 frames, 90 min, 4.4 mm FWHM) in 36 subjects using the radioligand [carbonyl-11C]WAY-100635, and a reference tissue model (MRTM2). In fMRI (3T, EPI inplane resolution 1.6*2.7 mm, 10 AC-PC orientated slices, ST = 3 mm, TE/TR = 31/1000 ms), 32 participants performed emotion discrimination and sensorimotor control tasks. Statistical analysis with SPM5 and unpaired t-tests were performed on molecular and functional data separately.

Results

The astrocytoma was delineated in the serotonin-1A receptor distribution showing (p < 0.01, uncorrected) regional BPND decrease. The ipsilateral thalamus and bilateral habenula regions displayed (p < 0.001; uncorrected) BPND increase. The fMRI data showed significantly (p < 0.05; uncorrected) reduced activation in the affected amygdalar region, ipsilateral fusiform gyrus, bilateral orbitofrontal cortex and temporal regions and increased activation in the contralateral temporal pole.

Conclusions

Lower serotonin-1A receptor binding in the left amydala region reflects the glial provenance of the tumor. The increased receptor binding in the habenulae might be associated with altered monoaminergic neurotransmission and depressive symptoms according to the influence of the habenulae on monoaminergic nuclei. The functional data demonstrate neuroplastic changes beyond affected areas and might indicate compensatory mechanisms.

Electroconvulsive therapy is equally effective in unipolar and bipolar depression

OBJECTIVE

To determine the relative efficacy of electroconvulsive therapy (ECT) in the treatment of bipolar (BP) and unipolar (UP) depressive illness and clarify its role in BP depression.

METHOD

Patients referred for ECT with both UP and BP depressions. [classified by Structured Clinical Interview for DSM (SCID-I) criteria for history of mania] were included in a multi-site collaborative, double-masked, randomized controlled trial of three electrode placements - right unilateral, bifrontal or bitemporal - in a permutated block randomization scheme.

RESULTS

Of 220 patients, 170 patients (77.3%) were classified as UP and 50 (22.7%) as BP depression in the intent-to-treat sample. The remission and response rates and numbers of ECT for both groups were equivalent.

CONCLUSION

Both UP and BP depressions remit with ECT. Polarity is not a factor in the response rate. In this sample ECT did not precipitate mania in depressed patients. Treatment algorithms for UP and BP depression warrant re-evaluation.

Measuring the transmission matrix in optics: an approach to the study and control of light propagation in disordered media

We introduce a method to experimentally measure the monochromatic transmission matrix of a complex medium in optics. This method is based on a spatial phase modulator together with a full-field interferometric measurement on a camera. We determine the transmission matrix of a thick random scattering sample. We show that this matrix exhibits statistical properties in good agreement with random matrix theory and allows light focusing and imaging through the random medium. This method might give important insight into the mesoscopic properties of a complex medium.

Bifrontal, bitemporal and right unilateral electrode placement in ECT: randomised trial

BACKGROUND

Electroconvulsive therapy (ECT) is an effective treatment for major depression. Optimising efficacy and minimising cognitive impairment are goals of ongoing technical refinements.

AIMS

To compare the efficacy and cognitive effects of a novel electrode placement, bifrontal, with two standard electrode placements, bitemporal and right unilateral in ECT.

METHOD

This multicentre randomised, double-blind, controlled trial (NCT00069407) was carried out from 2001 to 2006. A total of 230 individuals with major depression, bipolar and unipolar, were randomly assigned to one of three electrode placements during a course of ECT: bifrontal at one and a half times seizure threshold, bitemporal at one and a half times seizure threshold and right unilateral at six times seizure threshold.

RESULTS

All three electrode placements resulted in both clinically and statistically significant antidepressant outcomes. Remission rates were 55% (95% CI 43-66%) with right unilateral, 61% with bifrontal (95% CI 50-71%) and 64% (95% CI 53-75%) with bitemporal. Bitemporal resulted in a more rapid decline in symptom ratings over the early course of treatment. Cognitive data revealed few differences between the electrode placements on a variety of neuropsychological instruments.

CONCLUSIONS

Each electrode placement is a very effective antidepressant treatment when given with appropriate electrical dosing. Bitemporal leads to more rapid symptom reduction and should be considered the preferred placement for urgent clinical situations. The cognitive profile of bifrontal is not substantially different from that of bitemporal.

Catatonia is not schizophrenia: Kraepelin's error and the need to recognize catatonia as an independent syndrome in medical nomenclature

Catatonia is a motor dysregulation syndrome described by Karl Kahlbaum in 1874. He understood catatonia as a disease of its own. Others quickly recognized it among diverse disorders, but Emil Kraepelin made it a linchpin of his concept of dementia praecox. Eugen Bleuler endorsed this singular association. During the 20th century, catatonia has been considered a type of schizophrenia. In the 1970s, American authors identified catatonia in patients with mania and depression, as a toxic response, and in general medical and neurologic illnesses. It was only occasionally found in patients with schizophrenia. When looked for, catatonia is found in 10% or more of acute psychiatric admissions. It is readily diagnosable, verifiable by a lorazepam challenge test, and rapidly treatable. Even in its most lethal forms, it responds to high doses of lorazepam or to electroconvulsive therapy. These treatments are not accepted for patients with schizophrenia. Prompt recognition and treatment saves lives. It is time to place catatonia into its own home in the psychiatric classification.

A randomized controlled trial comparing the memory effects of continuation electroconvulsive therapy versus continuation pharmacotherapy: results from the Consortium for Research in ECT (CORE) study

OBJECTIVE

To compare the memory effects of continuation electroconvulsive therapy (C-ECT) versus continuation pharmacologic intervention (C-PHARM) at 12 and 24 weeks after completion of acute electroconvulsive therapy (ECT).

METHOD

Eighty-five patients with Structured Clinical Interview for DSM-IV-diagnosed unipolar major depressive disorder, enrolled in a multisite, randomized, parallel-design trial conducted at 5 academic medical centers from 1997 to 2004, who had remitted with an acute course of bilateral ECT and remained unrelapsed through 24 weeks of continuation therapy, were included in this analysis. They were randomly assigned to C-ECT (10 treatments) or nortriptyline plus lithium (monitored by serum blood levels) for 24 weeks. Objective neuropsychological measures of retrograde and anterograde memory and subjective assessment of memory were obtained at baseline, 12 weeks, and 24 weeks. The Rey Auditory-Verbal Learning Test and the Autobiographical Memory Interview were the primary outcome measures.

RESULTS

The C-PHARM group showed a greater group difference (P < .01) for baseline to 12-week change for the Autobiographical Memory Interview. No other memory measures showed group differences for change scores from baseline to 12 weeks. Groups showed no baseline to 24-week change-score differences on any of the memory measures. For both groups, 12-week objective anterograde memory scores (eg, Auditory-Verbal Learning Test percent retention P = .0001; Rey-Osterrieth Complex Figure or Taylor Figure percent retention P < .002) and 24-week subjective memory scores were significantly improved (Squire Subjective Memory Questionnaire P < .02) over baseline. This result reflects the apparent resolution of a presumed decrement in anterograde memory associated with acute ECT preceding this study.

CONCLUSIONS

The finding of no memory outcome differences between unrelapsed recipients of C-ECT and C-PHARM is consistent with clinical experience. Memory effects have only a small role in the choice between C-ECT and C-PHARM.

MR-guided transcranial brain HIFU in small animal models

Recent studies have demonstrated the feasibility of transcranial high-intensity focused ultrasound (HIFU) therapy in the brain using adaptive focusing techniques. However, the complexity of the procedures imposes provision of accurate targeting, monitoring and control of this emerging therapeutic modality in order to ensure the safety of the treatment and avoid potential damaging effects of ultrasound on healthy tissues. For these purposes, a complete workflow and setup for HIFU treatment under magnetic resonance (MR) guidance is proposed and implemented in rats. For the first time, tissue displacements induced by the acoustic radiation force are detected in vivo in brain tissues and measured quantitatively using motion-sensitive MR sequences. Such a valuable target control prior to treatment assesses the quality of the focusing pattern in situ and enables us to estimate the acoustic intensity at focus. This MR-acoustic radiation force imaging is then correlated with conventional MR-thermometry sequences which are used to follow the temperature changes during the HIFU therapeutic session. Last, pre- and post-treatment magnetic resonance elastography (MRE) datasets are acquired and evaluated as a new potential way to non-invasively control the stiffness changes due to the presence of thermal necrosis. As a proof of concept, MR-guided HIFU is performed in vitro in turkey breast samples and in vivo in transcranial rat brain experiments. The experiments are conducted using a dedicated MR-compatible HIFU setup in a high-field MRI scanner (7 T). Results obtained on rats confirmed that both the MR localization of the US focal point and the pre- and post-HIFU measurement of the tissue stiffness, together with temperature control during HIFU are feasible and valuable techniques for efficient monitoring of HIFU in the brain. Brain elasticity appears to be more sensitive to the presence of oedema than to tissue necrosis.